Speedometer



`motherobjectisto o jects by a` construction Vwherein one of `the two d parts of the `combined instrument nisivisible` l `throughfaltransparentmernber associatedwwith o maar stile F;

UNITEDSTATES..PAfrENryOFFICE o o Bacitrline eden-"f n eral Motors Corporation, Detroit, lcon-or L] '"Ihis invention relates tothe illumination `oi `inrlicating instrumentsand has been designed `"more `particularly` as an: improved provision ior"` the illumination; of i a speedometer `and odometer 5 @combination for` use .on vehicles; `1

Ann object ci; the invention is to improvethe,I illumination of p theispeedtand vdistance o `Another object'istto provide such illumination `z J as willconceal the lightiiromlasourceexcept such y light as is; directed tothe ylzuirtsiwhicl'i need tof'be i the otherupart lofutl'ie instrumentw i i n Other :objects 4and `iuziwintages will belfunder'f p l" stood from the followingndescription!"l speedometer and odometerm `On the drawings: l l Figure-1 `isa view in` elevationyo apicornbiried n i Figure 2 is" a vertical section L s line 2-2qoi Figure 1."

modied form. o n; i o

`Figure `4` is a `vertical half sectionthrough" an n other" n iorm n of the "invention employing ai sinne` whatcliierentmethoiloi.'illumiriationr]"` n i o t Figure 5 is a. view `inelevationof thefinstru u mentl shown in l Figure Fas seenifacingfthe `front.` i i Figure 6 isa perspectiveofz-onefotutliefparts i fused with;thelmechanismlshowninFigureA; v

1 Figure 7 is a perspectiveilof faipart whichymay `be used; in place ofythepartshovvn in #Figure 6.

i 3 Referringby reference "characters "rstfto` Fig-` pureslfand 2.numeral il represents a cup-shaped member carrying@` `operating mechanisnrfnot ylatter is iasteried liousingli havingiaiange I'I. `A bezel `I9 isiusedgto secure inpositiori relaltivetohousing I5 andflother parts oidthe instru- [ment a. metal :plate liand a. glass "cover 2l.

` Becuredto and `extending `through `an opening glass are markings 26 which takefthe form of o numerals to represent the speed at whichlth'e vehicle is traveling.` light transmitted `the `glass through openings?! ispinteriorly` re-3 markings `1 accomplish..the` above ob``` i o o o l f sociated wlththespeedometerframe marked 3L "Theuiodometer comprises `a 'plurality ofwflgure wheelssbestfshownin Figure 1. These figures u; arefseenbythe observer through glass `23, through the large opening Il within plate Hand throughyopeningsl in-` another plate" 31,' `this zplate` I'I being suitably secured by" fastening means notsliownlion the'frontfot the frame 3D of o t "i ithecombined"instrument 'I'hefplate 31 covers bgtantially `mi` 1lthemoperatirigqjparts` oithe instrument and to i getherxiwithplatefll `prevents the direct light Figure `3;;1 is ia" similar :section-fbut:showingja l riiaeizie'i tiirougii i ,the 'glass and refractedaud nien Hreected i'romthelaniarkingsb "Atnight the glass?` as "a whole is not invisible.'only` the" etched regions being` visible to the observer. f

o f induits color caribe controlled by painting the front wsurface of the glass opposite openings` 2l`feither white or sorneotherfdesired color.` :The white or lmiiniaifeui:` surfacev aids" in dispersing the iight l througli` n the yglass "therebyV improving the t lighted ppearance of i the numerals.

odorrieter4 mechanism, "this"mech`a`nism being as- "fromtth Abulbfl from" reaching o the observer. n

"Td accomplish this resultgit will be`seen that The speedometer mechanismis providedwith a rotatingyspindleextending through an enflAt `3i isrepresente more'or less conventional i larged` centralopening 4I in plate I'I. Stem'39 n has securediai its andthe pointers: ai Lucitv surface of the pointer facinglthe observerls :paintedpivhite pas `showxijiitj and clamped to this"central part `or the pointer-is a metallic `opaque shieldT 41". This shield prevents the trans-` mission of "any light from :the central part of the pointer to the observer. `(im the outer extremity @of the pointer-:arid on thefside remote from the `1observeris a `second".paintedregiori 49. That partfof the pointer between thetwo painted regions is unpsinted and asseenfinFigureZlit is the `unpainted and n -theretore transparent `part;

" which passes `over the odometer` heures. `The light from bulblp'l illuminates-the pivoted part ofthe misteriosi u, `theliantconcluir through `opening "l if "-'Aiterbeing "reiieeted Strom Vpainted,surface o il iight is internally ieiiecuui through the pointer tothe paintedsurface 49 from which it `is reflected to the observer. It will be `understood that the positionfof the painted surface 49 relativetouthemarkings on the glass plate 2l indicateithe rate of` "travel o! the `vehicle. At the `saine time the observer may read the mileage or other trahsporentmaterial. `At its .center the o y ing.V rOi? vrthe speedometer mechanism the observer sees only the illuminated figures and thetip of traveled not only through the parts heretofore mentioned but through the unpainted part of the pointer which passes over the ngures lo! they odometer mechanism. By the Vuse of the construction above described no direct light reaches the observer from the bulb 21 within'the housthe pointer. He'reads the odorneterbyl the light within the housing reflected from the odometerV wheels and transmitted'through openings.

In Figure 3 1s shown a slight modification. TheH f parts of the housing shown in this lfigure which correspond with similarfpartsrin Figure il' are marked with similar but primed rl'eiereii'ce"charv acters. In. this second form of the inventionthe ypointer 43' hastwo painted regions, one il im' mediately in front ofthe opaque wall 31' but behind the opaque wall 2l', and the other 33 being Aradially inward from the region 6 I.` `In this form of the inventionthe light from bulb 21passes between'the outer edge: of -plate`31' and-platen' and then through the` end Aof the transparent pointer to the painted-surface Si. By internal vreilection lthe light is transmittedto vsurface 63 v from which it is reflected to thel observerjas-before through theopening lin plate Zi'- andthe ,f glass 23. The odometer isvisible in precisely.-

the same way as the form shown inA Figure 2.;

` parent disc 1l.

In Figures 4 to 6 another` form Vof pointer is used. In these, figures the housingis substantially like that shown in Figure 1 and the parts arek similarly identified by reference characters. .Y The opaque plate` 31"y diiiers from -fplate31 in that vit lacks the large central opening forl the;

passage of light, Vhavingmerely a small aperture 38 for the passage of the speedometer spindle 39.' Plate 31" has;` an opening 35V through which vthe odometer is visible as before, Thelspeedyometer spindle 39 carries the modified forml of pointer. The pointer yis Va transparent `disc 1i` circular in outline. About its periphery isa metal ring 13 U-shaped -in' section.- This ring may ber crimped over the marginal edge of the disc 1i. At one point in the periphery the ring 13 has a,

painted tip 15. Light'from thevbulb 21v passes betwen the'platell and theouteredge of the`r kplate 31" and` is reflected from the tip 15. f The position ofithis tip relative tothe iiguresetched vin the glass indicates car speed. Theodometer figures are seen through glass 23,`through the large opening in plate In Figure 'l there is 'shown` a slight modification of the pointer disc. It is marked by numeral 1I. Formed on itsh peripheral .marginisfagrim 13', the rim'being oflthe same material as the ,Y disc and at vone point on its periphery there is painted a'tip 15'.,$I t `will be obvious that .the light is transmitted from thesource to lillumisource, the outer of said' plateshaving an enlarged opening, a fined transparentdisc ini'ront nate the several partsfjust asin the case of the formshown in Figure 4. f

Iclaimf, T `1 f l. An indicating instrument comprising a housing, a light source therein, spaced inner and outer opaque plates having'overlapping regions ito prevent direct transmission of light'from said ,2i and :through the transof said outer plate and having spaced reflecting markings adapted to receive light from said source, movable means ybetween said opaque plates, said movable means being in part transparent and provided with a region to receive light from said source said movable means also constructed to reilect light to an "observer through said first mentioned transparent disc, a second indicating device having movable elements lo,- cated within said housing, the inner one of said opaque plates having an openingfwhereby said last named elements may be seen through said opening, said transparent movable means, the

""opening'in the outer of said opaque platesand through said mentioned transparent disc.

2. The invention defined by claim l, the outer ofsaid opaqueplates having openings to receive light from said source fortransmission to said 'markings'on said" first transparent disc.

.3; An indicating instrument comprising a housing, `a light source therein., spaced opaque plates Vwithin saidk housing andhaving `overlapping regions to prevent the transmission of direct light from said source, a Vfixed transparent disc' `having spaced reflecting markings adapted lto receive light.. from saidsource, movable means between said. opaque plates, said movable means `being in-` part transparent but providedlwith lspaced painted areas-,.one'ofsaid areas positioned to receive light from said source vand the other to reflect light to the observer through the transp parent disc, a ,second indicating device having movable elements `and located within said housing, the innerfone of saidv plates having an opening whereby said last named' elements maybe parent disc.,l

; 4.v lThe inventionfdefined `by claim 3, said 'areas p plates having anvopening Yto-transmit light from the housing to1said central' areas, the outer oi' `seenV through said opening, said transparent move able means, an opening `through the outeropaque plate 'and through saidl first.r mentioned transsaid. area;y being adjacent `the outer margin of g said movablemeans and opposite an openingin the outer opaque plate.

v6. An indicating instrumentv rcomprising a member having scale markings,.l an opaque elelment having an opening therein,- areg'ister posi'- tioned 4to .be4 visiblel through said opening, Aan

kelongated v'movable pointer on lthe side of thev` opaque element remote from the register, saidV pointer cooperating with Asaid scale markings,

a source of light to illuminate said register, said pointerand scale markings,- said pointerhaving light receiving andlight reilecting regions and a portiontherebetween adapted to transmit lightr by, internal reilection, thereinand between said vregions andalsol rizo/render said register visible therethrough r'. Bacon. 

